setting up a new cold water tank

[wanttosinglikemarycoughlan]

I want to set up a cold water tank with the smallest cold water fish possible
I have had goldfish in the past but 10 or more years ago. I had a big tank with lots of swimming space
Can anyone advise on size of tank for smaller fish and any other advice?

You could keep a small shoal of minnows in a 60 litre tank. That's about as small as you could go for coldwater. Have you got a size limit?

No size limit
I just like the look of smaller fish
Approx how many would be happy together?

With shoaling fish you need 6+ really, to help spread the aggression evenly. If you have fewer than that then you can end up with a smaller, weaker one that gets picked on by all the others. There's no upper limit to how many you can have in a shoal, you're only limited by tank size. In a 60 litre tank I'd probably have 8 minnows.